Canadian Airway Focus Group updated consensus-based recommendations for management of the difficult airway: part 1. Difficult airway management encountered in an unconscious patient.

PURPOSE: Since the last Canadian Airway Focus Group (CAFG) guidelines were published in 2013, the literature on airway management has expanded substantially. The CAFG therefore re-convened to examine this literature and update practice recommendations. This first of two articles addresses difficulty encountered with airway management in an unconscious patient. SOURCE: Canadian Airway Focus Group members, including anesthesia, emergency medicine, and critical care physicians, were assigned topics to search. Searches were run in the Medline, EMBASE, Cochrane Central Register of Controlled Trials, and CINAHL databases. Results were presented to the group and discussed during video conferences every two weeks from April 2018 to July 2020. These CAFG recommendations are based on the best available published evidence. Where high-quality evidence was lacking, statements are based on group consensus. FINDINGS AND KEY RECOMMENDATIONS: Most studies comparing video laryngoscopy (VL) with direct laryngoscopy indicate a higher first attempt and overall success rate with VL, and lower complication rates. Thus, resources allowing, the CAFG now recommends use of VL with appropriately selected blade type to facilitate all tracheal intubations. If a first attempt at tracheal intubation or supraglottic airway (SGA) placement is unsuccessful, further attempts can be made as long as patient ventilation and oxygenation is maintained. Nevertheless, total attempts should be limited (to three or fewer) before declaring failure and pausing to consider "exit strategy" options. For failed intubation, exit strategy options in the still-oxygenated patient include awakening (if feasible), temporizing with an SGA, a single further attempt at tracheal intubation using a different technique, or front-of-neck airway access (FONA). Failure of tracheal intubation, face-mask ventilation, and SGA ventilation together with current or imminent hypoxemia defines a "cannot ventilate, cannot oxygenate" emergency. Neuromuscular blockade should be confirmed or established, and a single final attempt at face-mask ventilation, SGA placement, or tracheal intubation with hyper-angulated blade VL can be made, if it had not already been attempted. If ventilation remains impossible, emergency FONA should occur without delay using a scalpel-bougie-tube technique (in the adult patient). The CAFG recommends all institutions designate an individual as "airway lead" to help institute difficult airway protocols, ensure adequate training and equipment, and help with airway-related quality reviews.

RéSUMé: OBJECTIF: Depuis la dernière publication des lignes directrices du Canadian Airway Focus Group (CAFG) en 2013, la littérature sur la prise en charge des voies aériennes s'est considérablement étoffée. Le CAFG s'est donc réuni à nouveau pour examiner la littérature et mettre à jour ses recommandations de pratique. Ce premier article de deux traite de la prise en charge des voies aériennes difficiles chez un patient inconscient. SOURCES: Des sujets de recherche ont été assignés aux membres du Canadian Airway Focus Group, qui compte des médecins anesthésistes, urgentologues et intensivistes. Les recherches ont été menées dans les bases de données Medline, EMBASE, Cochrane Central Register of Controlled Trials et CINAHL. Les résultats ont été présentés au groupe et discutés lors de vidéoconférences toutes les deux semaines entre avril 2018 et juillet 2020. Les recommandations du CAFG sont fondées sur les meilleures données probantes publiées. Si les données probantes de haute qualité manquaient, les énoncés se fondent alors sur le consensus du groupe. CONSTATATIONS ET RECOMMANDATIONS CLéS: La plupart des études comparant la vidéolaryngoscopie à la laryngoscopie directe indiquent un taux de réussite plus élevé à la première tentative et globalement avec la vidéolaryngoscopie, ainsi que des taux de complication inférieurs. Ainsi, les ressources le permettant, le CAFG recommande dorénavant l'utilisation de vidéolaryngoscopes avec le type de lame convenablement sélectionné pour faciliter toutes les intubations trachéales. En cas d'échec de la première tentative d'intubation trachéale ou d'échec de positionnement du dispositif supraglottique (DSG), d'autres tentatives peuvent être entreprises tant que la ventilation et l'oxygénation du patient le permettent. Néanmoins, le nombre total de tentatives devrait être limité, à trois ou moins, avant de déclarer un échec et de considérer les options de « stratégie de retrait ¼. En cas d'échec de l'intubation, les options de stratégie de retrait chez un patient toujours oxygéné comprennent l'éveil (si possible), la temporisation avec un DSG, une dernière tentative d'intubation trachéale à l'aide d'une technique différente, ou une cricothyroïdotomie. L'échec de l'intubation trachéale, de la ventilation au masque facial et de la ventilation via un DSG accompagné d'une hypoxémie présente ou imminente, définit une urgence « impossible de ventiler, impossible d'oxygéner ¼. Le bloc neuromusculaire doit alors être confirmé ou mis en place, et une tentative finale de ventilation au masque, de positionnement du DSG ou d'intubation trachéale avec une lame de vidéolaryngoscopie hyper-angulée peut être réalisée, si cette approche n'a pas encore été essayée. Si la ventilation demeure impossible, une cricothyroïdotomie d'urgence devrait être réalisée sans délai utilisant une technique de scalpel-bougie-tube (chez le patient adulte). Le CAFG recommande à toutes les institutions de désigner une personne comme « leader des voies aériennes ¼ afin d'assister à la mise en place de protocoles pour les voies aériennes difficiles, d'assurer une formation et un équipement adéquats et d'aider aux examens de la qualité en rapport avec les voies aériennes.

Canadian Airway Focus Group updated consensus-based recommendations for management of the difficult airway: part 2. Planning and implementing safe management of the patient with an anticipated difficult airway.

PURPOSE: Since the last Canadian Airway Focus Group (CAFG) guidelines were published in 2013, the published airway management literature has expanded substantially. The CAFG therefore re-convened to examine this literature and update practice recommendations. This second of two articles addresses airway evaluation, decision-making, and safe implementation of an airway management strategy when difficulty is anticipated. SOURCE: Canadian Airway Focus Group members, including anesthesia, emergency medicine, and critical care physicians were assigned topics to search. Searches were run in the Medline, EMBASE, Cochrane Central Register of Controlled Trials, and CINAHL databases. Results were presented to the group and discussed during video conferences every two weeks from April 2018 to July 2020. These CAFG recommendations are based on the best available published evidence. Where high-quality evidence is lacking, statements are based on group consensus. FINDINGS AND KEY RECOMMENDATIONS: Prior to airway management, a documented strategy should be formulated for every patient, based on airway evaluation. Bedside examination should seek predictors of difficulty with face-mask ventilation (FMV), tracheal intubation using video- or direct laryngoscopy (VL or DL), supraglottic airway use, as well as emergency front of neck airway access. Patient physiology and contextual issues should also be assessed. Predicted difficulty should prompt careful decision-making on how most safely to proceed with airway management. Awake tracheal intubation may provide an extra margin of safety when impossible VL or DL is predicted, when difficulty is predicted with more than one mode of airway management (e.g., tracheal intubation and FMV), or when predicted difficulty coincides with significant physiologic or contextual issues. If managing the patient after the induction of general anesthesia despite predicted difficulty, team briefing should include triggers for moving from one technique to the next, expert assistance should be sourced, and required equipment should be present. Unanticipated difficulty with airway management can always occur, so the airway manager should have a strategy for difficulty occurring in every patient, and the institution must make difficult airway equipment readily available. Tracheal extubation of the at-risk patient must also be carefully planned, including assessment of the patient's tolerance for withdrawal of airway support and whether re-intubation might be difficult.

RéSUMé: OBJECTIF: Depuis la dernière publication des lignes directrices du Canadian Airway Focus Group (CAFG) en 2013, la littérature sur la prise en charge des voies aériennes s'est considérablement étoffée. Le CAFG s'est donc réuni à nouveau pour examiner la littérature et mettre à jour ses recommandations de pratique. Ce deuxième article traite de l'évaluation des voies aériennes, de la prise de décision et de la mise en œuvre sécuritaire d'une stratégie de prise en charge des voies aériennes lorsque des difficultés sont anticipées. SOURCES: Des sujets de recherche ont été assignés aux membres du Canadian Airway Focus Group, qui compte des médecins anesthésistes, urgentologues et intensivistes. Les recherches ont été réalisées dans les bases de données Medline, EMBASE, Cochrane Central Register of Controlled Trials et CINAHL. Les résultats ont été présentés au groupe et discutés lors de vidéoconférences toutes les deux semaines entre avril 2018 et juillet 2020. Les recommandations du CAFG sont fondées sur les meilleures données probantes publiées. Si les données probantes de haute qualité manquaient, les énoncés se fondent alors sur le consensus du groupe. CONSTATATIONS ET RECOMMANDATIONS CLéS: Avant d'amorcer la prise en charge des voies aériennes, une stratégie documentée devrait être formulée pour chaque patient, en fonction de l'évaluation de ses voies aériennes. L'examen au chevet devrait rechercher les prédicteurs de difficultés pour la ventilation au masque, l'intubation trachéale utilisant la vidéolaryngoscopie ou la laryngoscopie directe, l'utilisation d'un dispositif supraglottique, ainsi que pour la cricothyroïdotomie d'urgence. La physiologie du patient et ses problématiques contextuelles devraient également être évaluées. Les difficultés anticipées devraient inciter à prendre des décisions éclairées sur la façon la plus sécuritaire de procéder à la prise en charge des voies aériennes. L'intubation trachéale éveillée peut procurer une marge de sécurité supplémentaire lorsqu'on s'attend à ce que la vidéolaryngoscopie ou la laryngoscopie directe soient impossibles, lorsqu'on prévoit des difficultés pour plus d'un mode de prise en charge des voies aériennes (p. ex., intubation trachéale et ventilation au masque), ou lorsque la difficulté prévue coïncide avec des problèmes physiologiques ou contextuels importants. En cas de choix de prise en charge des voies respiratoires du patient après induction de l'anesthésie générale malgré les difficultés prévues, les directives à l'équipe devraient inclure les déclencheurs pour passer d'une technique à l'autre, l'aide d'experts disponibles et l'équipement requis disponible. Des difficultés imprévues lors de la prise en charge des voies aériennes peuvent toujours survenir, de sorte que la personne responsable de la prise en charge des voies aériennes devrait avoir une stratégie pour chaque patient, et l'établissement doit rendre facilement disponible le matériel pour la prise en charge des voies aériennes difficiles. L'extubation trachéale du patient à risque doit également être soigneusement planifiée, y compris l'évaluation de la tolérance du patient lors du retrait du dispositif de soutien des voies aériennes et d'une ré-intubation potentiellement difficile.

Simultaneous en bloc endotracheal tube insertion with GlideScope® Titanium™ video laryngoscope use: a randomized-controlled trial.

PURPOSE: Intubation-associated trauma with the GlideScope is rare, but when it occurs, it is likely due to advancing the endotracheal tube (ETT) blindly between the direct view of the oropharynx and the video view of the glottis. It is also occasionally difficult to advance the ETT to the glottic aperture despite a good view of the glottis on the monitor. One technique to potentially address both issues is to introduce the ETT en bloc with the GlideScope, thus visualizing the ETT tip throughout its entire path. We hypothesized that this en bloc technique could be faster and potentially easier than the standard technique. METHODS: Fifty patients with normal-appearing airways who required orotracheal intubation for elective surgery were randomly allocated to intubation with either the en bloc or the standard (GlideScope-first-then-ETT) technique. A three-dimensional printed clip was utilized to secure the ETT to the GlideScope during en bloc insertion. The primary outcome was time to intubation, defined from mask removal to first end-tidal carbon dioxide detection, recorded by a blinded observer. Secondary outcomes were subjective ease of intubation (100-mm visual analogue scale [VAS], 0 = easy; 100 = difficult), number of intubation attempts/failures, and incidence of oropharyngeal trauma (bleeding). RESULTS: The median [interquartile range (IQR)] intubation time was 36 [31-42] sec with the en bloc technique vs 41 [37-50] sec with the standard technique (difference in medians, 5 sec; 95% confidence interval [CI], 2 to 11; P = 0.008). The median [IQR] ease of intubation VAS was 11 [9-21] mm with the en bloc technique, and 15 [11-24] mm with the standard technique (difference in medians, 4 mm; 95% CI, -2 to 8; P = 0.19). Laryngoscopic grade and number of intubation attempts were similar between the groups; there was no oropharyngeal trauma noted. CONCLUSION: In this study of video laryngoscopy, intubation was slightly faster with the en bloc technique than with the standard GlideScope intubation technique, although the clinical importance of this difference is unknown. TRIAL REGISTRATION: www.clinicaltrials.gov (NCT02787629); registered 1 June 2016.

RéSUMé: OBJECTIF: Les traumatismes associés à l'intubation avec un GlideScope sont rares; quand ils surviennent, ils sont souvent provoqués par l'insertion du tube endotrachéal (TET) en aveugle entre la visualisation directe de l'oropharynx et la visualisation par vidéo de la glotte. Il arrive parfois qu'il soit difficile d'insérer le TET dans l'ouverture glottique malgré une bonne visualisation de la glotte sur le moniteur. Une technique permettant potentiellement de résoudre ces deux problèmes est l'introduction 'en bloc' du TET et du GlideScope, de manière à obtenir une vue de l'extrémité du TET tout au long de son parcours. Nous avons émis l'hypothèse que cette technique en bloc pourrait être à la fois plus rapide et potentiellement plus facile à réaliser que la technique standard. MéTHODE: Cinquante patients présentant des voies aériennes d'apparence normale et nécessitant une intubation orotrachéale pour une chirurgie non urgente ont été randomisés à être intubés soit par une technique en bloc, soit en utilisant la technique standard (GlideScope puis TET). Une pince imprimée en 3D a été utilisée pour attacher le TET au GlideScope pendant l'insertion en bloc. Le critère d'évaluation principal était le temps nécessaire à l'intubation, défini à partir du moment de retrait du masque jusqu'à la première détection de dioxyde de carbone télé-expiratoire, tel que mesuré par un observateur en aveugle. Les critères secondaires comprenaient la facilité subjective d'intubation (sur une échelle visuelle analogique [EVA] de 100 mm, où 0 = facile et 100 = difficile), le nombre de tentatives et d'échecs d'intubation, et l'incidence de lésions oropharyngées (saignement). RéSULTATS: Le temps d'intubation médian [écart interquartile (ÉIQ)] était de 36 [31­42] sec avec la technique en bloc vs 41 [37­50] sec avec la technique standard (différence de moyennes, 5 sec; intervalle de confiance [IC] 95 %, 2 à 11; P = 0,008). La facilité d'intubation médiane [ÉIQ] sur l'EVA était de 11 [9-21] mm avec la technique en bloc, et 15 [11-24] mm avec la technique standard (différence de moyennes, 4 mm; IC 95 %, -2 à 8; P = 0,19). La classification de la laryngoscopie et le nombre de tentatives d'intubation étaient similaires dans les deux groupes; aucun traumatisme oropharyngé n'a été enregistré. CONCLUSION: Dans cette étude vidéolaryngoscopique, l'intubation était légèrement plus rapide lors de l'utilisation de la technique en bloc que lors d'une technique d'intubation standard avec le GlideScope, bien que l'importance clinique de cette différence soit inconnue. ENREGISTREMENT DE L'éTUDE: www.clinicaltrials.gov (NCT02787629); enregistrée le 1er juin 2016.

The degree of adherence to CONSORT reporting guidelines for the abstracts of randomised clinical trials published in anaesthesia journals: A cross-sectional study of reporting adherence in 2010 and 2016.

BACKGROUND: Abstracts are intended to be concise summaries of the entire randomised clinical trial (RCT). Despite their importance, few studies have examined the reporting quality of abstracts in the anaesthesiology literature. OBJECTIVES: To examine the quality of RCT abstract reporting according to the CONSORT for Abstracts guidelines and determine whether recommended items omitted from the abstract were present in the body of the article. DESIGN: A cross-sectional study of RCTs. SETTING: This study was performed at the University of Western Ontario and University Hospital, London Health Sciences Centre. PARTICIPANTS: All RCTs meeting inclusion criteria that were published in 2010 or 2016 in six general anaesthesiology journals (Anaesthesia, Anesthesia & Analgesia, Anesthesiology, British Journal of Anaesthesia, Canadian Journal of Anesthesia and European Journal of Anaesthesiology). MAIN OUTCOME MEASURES: The 16 checklist items from the CONSORT for Abstracts statement were used to create a convenience score as a proxy for RCT abstract reporting quality, with each criterion measured as being reported in abstract, not reported in abstract but reported in full-text article, or not reported in abstract or full-text article. RESULTS: Of the 395 RCTs identified, 219 were published in 2010 and 176 were published in 2016. Out of the maximum possible score of 16, the median abstract score increased from 4 points [interquartile range (IQR): 3 to 5] in 2010 to 6 points [IQR: 5 to 8] in 2016. Although most checklist items showed improvement from 2010 to 2016, around 75% of RCTs in 2016 met fewer than half of the 16 items with no RCTs reporting all 16 items in the abstract. A majority of the RCTs had the information present in the full-text. In 2016, only 71 out of 176 (40%) of RCTs reported outcomes conforming to the CONSORT guidelines (with an effect size and a confidence interval around the effect size) in the Abstract. CONCLUSION: Abstracts for many anaesthesiology RCTs are incomplete selective summaries of the entire article.

Sample size calculations for randomized clinical trials published in anesthesiology journals: a comparison of 2010 versus 2016.

PURPOSE: Although every randomized clinical trial (RCT) needs participants, determining the ideal number of participants that balances limited resources and the ability to detect a real effect is difficult. Focussing on two-arm, parallel group, superiority RCTs published in six general anesthesiology journals, the objective of this study was to compare the quality of sample size calculations for RCTs published in 2010 vs 2016. METHODS: Each RCT's full text was searched for the presence of a sample size calculation, and the assumptions made by the investigators were compared with the actual values observed in the results. Analyses were only performed for sample size calculations that were amenable to replication, defined as using a clearly identified outcome that was continuous or binary in a standard sample size calculation procedure. RESULTS: The percentage of RCTs reporting all sample size calculation assumptions increased from 51% in 2010 to 84% in 2016. The difference between the values observed in the study and the expected values used for the sample size calculation for most RCTs was usually > 10% of the expected value, with negligible improvement from 2010 to 2016. CONCLUSION: While the reporting of sample size calculations improved from 2010 to 2016, the expected values in these sample size calculations often assumed effect sizes larger than those actually observed in the study. Since overly optimistic assumptions may systematically lead to underpowered RCTs, improvements in how to calculate and report sample sizes in anesthesiology research are needed.

Comparison of Registered and Reported Outcomes in Randomized Clinical Trials Published in Anesthesiology Journals.

BACKGROUND: Randomized clinical trials (RCTs) provide high-quality evidence for clinical decision-making. Trial registration is one of the many tools used to improve the reporting of RCTs by reducing publication bias and selective outcome reporting bias. The purpose of our study is to examine whether RCTs published in the top 6 general anesthesiology journals were adequately registered and whether the reported primary and secondary outcomes corresponded to the originally registered outcomes. METHODS: Following a prespecified protocol, an electronic database was used to systematically screen and extract data from RCTs published in the top 6 general anesthesiology journals by impact factor (Anaesthesia, Anesthesia & Analgesia, Anesthesiology, British Journal of Anaesthesia, Canadian Journal of Anesthesia, and European Journal of Anaesthesiology) during the years 2007, 2010, 2013, and 2015. A manual search of each journal's Table of Contents was performed (in duplicate) to identify eligible RCTs. An adequately registered trial was defined as being registered in a publicly available trials registry before the first patient being enrolled with an unambiguously defined primary outcome. For adequately registered trials, the outcomes registered in the trial registry were compared with the outcomes reported in the article, with outcome discrepancies documented and analyzed by the type of discrepancy. RESULTS: During the 4 years studied, there were 860 RCTs identified, with 102 RCTs determined to be adequately registered (12%). The proportion of adequately registered trials increased over time, with 38% of RCTs being adequately registered in 2015. The most common reason in 2015 for inadequate registration was registering the RCT after the first patient had already been enrolled. Among adequately registered trials, 92% had at least 1 primary or secondary outcome discrepancy. In 2015, 42% of RCTs had at least 1 primary outcome discrepancy, while 90% of RCTs had at least 1 secondary outcome discrepancy. CONCLUSIONS: Despite trial registration being an accepted best practice, RCTs published in anesthesiology journals have a high rate of inadequate registration. While mandating trial registration has increased the proportion of adequately registered trials over time, there is still an unacceptably high proportion of inadequately registered RCTs. Among adequately registered trials, there are high rates of discrepancies between registered and reported outcomes, suggesting a need to compare a published RCT with its trial registry entry to be able to fully assess the quality of the study. If clinicians base their decisions on evidence distorted by primary outcome switching, patient care could be negatively affected.

Preprocedural ultrasound assessment does not improve trainee performance of spinal anesthesia for obstetrical patients: a randomized controlled trial.

STUDY OBJECTIVE: This randomized controlled trial was designed to evaluate the efficacy of additional information from preprocedure ultrasound examination to aid anesthesiology trainees performing spinal anesthesia for obstetric patients. DESIGN: Trainee residents were randomly allocated to landmark technique and anatomy demonstration via ultrasound examination or landmark technique only for spinal anesthetic placement. SETTING: Obstetric delivery suite. PATIENTS: Eighty healthy obstetric patients undergoing elective cesarean delivery. INTERVENTION: Ultrasound examination prior to spinal anesthetic placement. MEASUREMENTS: The primary outcome was the number of attempts for the spinal anesthetic. Secondary outcomes included placement duration; block height; and the incidence of need for staff intervention, paresthesia, and bloody tap. Subjective ease of placement was rated on a 100-mm visual analog scale. MAIN RESULTS: Baseline demographic data were similar between the patient groups. The median number of attempts with preprocedure ultrasound and landmark was 3 (interquartile range, 2-7). This was not significantly different from the number of attempts with landmark technique only of 3 (1-60) (P=.69). The median duration of spinal placement with ultrasound and landmark was 92 (51-140) seconds vs 75 (53-126) seconds with landmark only (P=.57). There was no statistical difference between the groups in spinal placement duration, need for staff intervention, paresthesia, bloody tap, lumbar interspace, or block height. There was no difference in subjective ease of spinal placement by the resident. CONCLUSIONS: In this study of junior anesthesia trainees performing obstetrical spinal anesthesia with preprocedure ultrasound and landmark technique or landmark technique only, no significant difference was observed in the number of attempts, duration of spinal placement, subjective ease of spinal placement, or any other measured secondary outcome.

Early Endotracheal Tube Insertion with the GlideScope: A Randomized Controlled Trial.

BACKGROUND: The GlideScope videolaryngoscope is an intubating device routinely used by anesthesiologists for tracheal intubation. It is occasionally difficult to advance the endotracheal tube (ETT) into the trachea, despite a good view of the glottis. One technique that may be used when difficulty is encountered is to remove the GlideScope from the pharynx and introduce the ETT into the pharynx first, leaving it in place posteriorly while the GlideScope is inserted. Frequently, when the GlideScope is subsequently inserted, the ETT tip will then be in good view, resting near the glottis, and will easily advance into the trachea. In this randomized, single-blinded trial, we assessed whether orotracheal intubation with the GlideScope is faster and/or easier with the ETT-first technique as a primary technique in elective patients. METHODS: One hundred sixty patients with normal-appearing airways who required elective orotracheal intubation were allocated randomly to intubation with insertion of the ETT or GlideScope into the oropharynx first. The primary outcome was time to intubation. The secondary outcomes were subjective ease of intubation (100-mm visual analog scale, 0 = easy; 100 = difficult), number of attempts/failures, incidence of oropharyngeal bleeding, and postoperative sore throat and/or vocal changes. RESULTS: Baseline demographics were similar between the 2 groups. Mean time to intubation was 48.2 ± 17.1 seconds with the ETT-first technique and 51.5 ± 21.8 seconds with the GlideScope-first technique (P = 0.30). The mean difference was 3.3 seconds in favor of the ETT-first technique (95% confidence interval, -2.9 to 9.6). The median ease of intubation using the visual analog scale was 13.3 mm (interquartile range, 5.3 to 21) with the ETT-first technique and 13.5 mm (interquartile range, 5.6 to 29.5) with the GlideScope-first technique (P = 0.30). The difference between the medians was -2.0 mm in favor of the ETT-first group (95% confidence interval, -1.5 to 6.0). There was no difference between groups for number of intubation attempts, incidence of oropharyngeal bleeding, laryngoscopic grade, sore throat, or vocal changes. CONCLUSIONS: In this study of GlideScope laryngoscopy, no statistically significant difference was observed in the time to intubate or the subjective ease of intubation whether the ETT or GlideScope was inserted into the oropharynx first.

The difficult airway with recommendations for management--part 2--the anticipated difficult airway.

BACKGROUND: Appropriate planning is crucial to avoid morbidity and mortality when difficulty is anticipated with airway management. Many guidelines developed by national societies have focused on management of difficulty encountered in the unconscious patient; however, little guidance appears in the literature on how best to approach the patient with an anticipated difficult airway. METHODS: To review this and other subjects, the Canadian Airway Focus Group (CAFG) was re-formed. With representation from anesthesiology, emergency medicine, and critical care, CAFG members were assigned topics for review. As literature reviews were completed, results were presented and discussed during teleconferences and two face-to-face meetings. When appropriate, evidence- or consensus-based recommendations were made, and levels of evidence were assigned. PRINCIPAL FINDINGS: Previously published predictors of difficult direct laryngoscopy are widely known. More recent studies report predictors of difficult face mask ventilation, video laryngoscopy, use of a supraglottic device, and cricothyrotomy. All are important facets of a complete airway evaluation and must be considered when difficulty is anticipated with airway management. Many studies now document the increasing patient morbidity that occurs with multiple attempts at tracheal intubation. Therefore, when difficulty is anticipated, tracheal intubation after induction of general anesthesia should be considered only when success with the chosen device(s) can be predicted in a maximum of three attempts. Concomitant predicted difficulty using oxygenation by face mask or supraglottic device ventilation as a fallback makes an awake approach advisable. Contextual issues, such as patient cooperation, availability of additional skilled help, and the clinician's experience, must also be considered in deciding the appropriate strategy. CONCLUSIONS: With an appropriate airway evaluation and consideration of relevant contextual issues, a rational decision can be made on whether an awake approach to tracheal intubation will maximize patient safety or if airway management can safely proceed after induction of general anesthesia. With predicted difficulty, close attention should be paid to details of implementing the chosen approach. This should include having a plan in case of the failure of tracheal intubation or patient oxygenation.

The difficult airway with recommendations for management--part 1--difficult tracheal intubation encountered in an unconscious/induced patient.

BACKGROUND: Previously active in the mid-1990s, the Canadian Airway Focus Group (CAFG) studied the unanticipated difficult airway and made recommendations on management in a 1998 publication. The CAFG has since reconvened to examine more recent scientific literature on airway management. The Focus Group's mandate for this article was to arrive at updated practice recommendations for management of the unconscious/induced patient in whom difficult or failed tracheal intubation is encountered. METHODS: Nineteen clinicians with backgrounds in anesthesia, emergency medicine, and intensive care joined this iteration of the CAFG. Each member was assigned topics and conducted reviews of Medline, EMBASE, and Cochrane databases. Results were presented and discussed during multiple teleconferences and two face-to-face meetings. When appropriate, evidence- or consensus-based recommendations were made together with assigned levels of evidence modelled after previously published criteria. CONCLUSIONS: The clinician must be aware of the potential for harm to the patient that can occur with multiple attempts at tracheal intubation. This likelihood can be minimized by moving early from an unsuccessful primary intubation technique to an alternative "Plan B" technique if oxygenation by face mask or ventilation using a supraglottic device is non-problematic. Irrespective of the technique(s) used, failure to achieve successful tracheal intubation in a maximum of three attempts defines failed tracheal intubation and signals the need to engage an exit strategy. Failure to oxygenate by face mask or supraglottic device ventilation occurring in conjunction with failed tracheal intubation defines a failed oxygenation, "cannot intubate, cannot oxygenate" situation. Cricothyrotomy must then be undertaken without delay, although if not already tried, an expedited and concurrent attempt can be made to place a supraglottic device.

The Flex-Tip™ tracheal tube does not reduce the incidence of postoperative sore throat: a randomized controlled trial.

PURPOSE: Sore throat after tracheal intubation is common with an incidence of 30-70%. The Parker Flex-Tip™ endotracheal tube (ETT) is designed to reduce trauma during ETT placement. This randomized single-blinded trial was designed to assess whether using the Flex-Tip ETT would reduce the incidence of postoperative sore throat and/or vocal change. METHODS: A Flex-Tip or a Mallinckrodt Hi-Lo® cuffed ETT was used by random allocation in 200 patients with normal-appearing airways requiring elective orotracheal intubation. On the second postoperative day, a blinded assessor recorded the incidence and severity of postoperative sore throat and voice alteration. The primary outcome was the incidence of moderate or severe sore throat. Secondary outcomes included vocal change, time to intubation, number of attempts/failures, incidence of oropharyngeal bleeding, and subjective ease of intubation. RESULTS: Demographic data were similar between the two groups. Moderate or severe sore throat was observed in 12% of patients with the Flex-Tip ETT and 6% of patients with the Mallinckrodt Hi-Lo ETT (odds ratio [OR] 2.1; 95% confidence intervals [CI] 0.70 to 7.1; P = 0.14). The incidence of moderate or severe vocal change was 6% and 3%, respectively (OR 2.0; 95% CI 0.42 to 12.9; P = 0.50). Time to intubation, number of intubation attempts, incidence of oropharyngeal bleeding, and ease of intubation did not differ significantly between groups. CONCLUSION: In this study involving experienced clinicians, no significant difference was observed in the incidence of postoperative sore throat or vocal change between the Flex-Tip ETT and the standard Mallinckrodt Hi-Lo cuffed ETT. This trial was registered at www.clinicaltrials.gov , NCT01095861.

A randomized comparison of the GlideRite(®) Rigid Stylet to a malleable stylet for orotracheal intubation by novices using the GlideScope(®).

PURPOSE: A stylet is usually necessary when using the GlideScope(®) videolaryngoscope for orotracheal intubation. A special stylet, the GlideRite(®) Rigid Stylet (GRS), was designed for this purpose. A previous trial involving experienced operators showed that the GRS offered no performance improvement vs a standard malleable stylet (SMS). In our trial, we compared the performance of the GRS with that of the SMS in terms of time to intubation and ease of intubation when used by novice GlideScope(®) operators. METHODS: Sixty patients with normal-appearing airways requiring orotracheal intubation for elective surgery were randomly allocated to be intubated by novice operators with the GlideScope(®), using either the GRS or the SMS. Time to intubation was assessed by a blinded observer, and the operators were blinded until just prior to tracheal intubation. Ease of intubation was assessed by a five-point ordinal scale (from 1- easy to 5 -difficult). Intubation attempts/failures, glottic grades, and usage of external laryngeal manipulation were recorded. RESULTS: There were no significant differences between the GRS and the SMS in terms of the median time to intubation (60 sec, interquartile range [IQR] 48-75 vs 61 sec, IQR 49-75, respectively; P = 0.94) and the ease of intubation (GRS median score: 1.5, IQR 1-2 vs SMS median score: 1, IQR 1-2; P = 0.94). There were no other significant differences between groups. CONCLUSION: The GRS and the SMS have similar performance characteristics when used by novice operators for GlideScope(®)-assisted orotracheal intubation. (Registered at ClinicalTrials.gov: NCT00884754).

Comparison of a single-use GlideScope Cobalt videolaryngoscope with a conventional GlideScope for orotracheal intubation.

BACKGROUND: This study was conceived to compare the single-use GlideScope Cobalt videolaryngoscope with the conventional GlideScope videolaryngoscope for orotracheal intubation, as judged by time to intubation (TTI) and ease of intubation. METHODS: One hundred patients with normal-appearing airways requiring orotracheal intubation for elective surgery were randomly allocated to have their tracheas intubated by a heterogeneous group of operators with the Cobalt GlideScope or the conventional GlideScope. TTI was assessed by a blinded observer. Operators were blinded until the start of laryngoscopy. A visual analogue scale (VAS) assessed the ease of intubation. The number of intubation attempts, number of failures, glottic grades, and fogging of the video screen were recorded. RESULTS: There was no difference between the median TTI of the GlideScope Cobalt and the conventional GlideScope (40.1 sec, interquartile range [IQR] 34.1, 51.3 vs 39 sec, IQR 32.6, 48.1, respectively; P = 0.75). The ease of intubation was similar between the two devices (median Cobalt VAS: 16 mm, IQR 10.8, 27.3, vs median conventional VAS: 12.5 mm, IQR 10, 20.5, respectively; P = 0.12). There were no significant differences between the two devices with respect to glottic exposure, intubation attempts, failures, or video screen fogging. CONCLUSIONS: The GlideScope Cobalt has similar performance characteristics compared with the conventional GlideScope videolaryngoscope when used for orotracheal intubation. The two devices can likely be used interchangeably. (ClinicalTrials.gov number, NCT00459797.).

The Flex-It stylet is less effective than a malleable stylet for orotracheal intubation using the GlideScope.

BACKGROUND: The GlideScope videolaryngoscope (Verathon Medical, Bothell, WA) usually provides excellent glottic visualization, but directing an endotracheal tube through the vocal cords can be challenging. The goal of the study was to compare the dedicated Flex-It stylet (FIS, Parker Medical, Highlands Ranch, CO) with a malleable stylet, as assessed by time to intubation (TTI). METHODS: Eighty patients requiring orotracheal intubation for elective surgery were randomly allocated to either the FIS or a malleable stylet (control) to facilitate tracheal intubation using the GlideScope. TTI was recorded by blinded assessors; operators were blinded until after laryngoscopy. The operator assessed the ease of intubation using a 100-mm visual analog scale (0 = easy to 100 = difficult). The number of intubation attempts, number of failures, glottic grades, and use of external laryngeal manipulation were documented. RESULTS: The median TTI was 41 s (interquartile range [IQR] 30-51) for the Flex-It group compared with 32 s (IQR 28-42) for the control group (P = 0.03). The median visual analog scale score for ease of intubation was 20 (IQR 11-39) for the Flex-It group compared with 15 (IQR 8-28) for the control group (P = 0.13). The overall incidence of a Cormack-Lehane Grade I or II glottic view was 100%. CONCLUSIONS: In a group of experienced operators using the GlideScope, the FIS was less effective for orotracheal intubation than a malleable endotracheal tube stylet.